A warning by Ciena Corp. of another revenue shortfall sent investor confidence in the Maryland company to a new low yesterday.

The telecommunications company, once one of the nation's hottest fiber-optic-equipment makers, lost a quarter of its market value in a broad sell-off of its stock. It closed lower than ever, at $2.08 a share, down 68 cents.

Ciena said on Tuesday, after the markets closed, that a combination of problems, including difficulty digesting recent acquisitions and a weak business environment, caused its most recent quarterly revenue to fall below the level it previously predicted.

Wall Street, already leery of Ciena's acquisition strategy, pounded the stock. At least four analysts issued downgrades yesterday, producing a wave of critical commentary about the company.

"Ciena's business model continues to be lumpy," J.P. Morgan Securities Inc. analyst Ehud A. Gelblum wrote in a report issued yesterday morning. J.P. Morgan has done investment banking business with Ciena in the past 12 months.

"Clearly, management is struggling with the integration of . . . acquisitions in a hostile spending environment that is not likely to change soon," wrote Friedman, Billings, Ramsey analyst Susan B. Kalla.

Ciena "pre-announced" its quarterly results, meaning it indicated what its revenue and some other performance measurements would be even though all the figures aren't in yet. The Linthicum company's third fiscal quarter ended Saturday. Earlier this summer, Ciena told investors that it expected revenue of about $95 million, but Tuesday it said revenue would be about $75 million.

It was the third straight quarter Ciena failed to meet its announced revenue targets.

Chief executive Gary B. Smith said the failure to reach the targets was not an indictment of his acquisition strategy, though he acknowledged that integrating two recent acquisitions has caused "more disruption than anticipated." Ciena has acquired five companies in the past two years, spending more than $1.6 billion in cash and stock.

Ciena has sought to ride out the slump in telecommunications spending by diversifying from its core business, which is making equipment that directs signals over long stretches of fiber-optic lines.

Its February acquisitions of Internet Photonics and Catena Networks gave it a toehold in the market for equipment designed to direct broadband signals near the end of the line -- for example, to one home DSL user instead of his neighbor. The acquisitions were intended to position Ciena to capitalize on the rapid growth of DSL connections offered by phone companies.

In a conference call with analysts Tuesday night, Smith said the company's customers are chiefly concerned with rolling out broadband Internet service to as many customers as possible.

"While it's certainly taking longer that we would like for the pieces to come together, we continue to get the kind of feedback from our customers that suggest we've taken the right steps at the right time," Smith said.

Smith told analysts, however, that in recent weeks there has been a "deceleration" in the growth of DSL line deployment, which dampened orders for equipment from Catena and Internet Photonics. Some large customers delayed orders that were scheduled to close in the third quarter, the company said.

In response to a question, Smith said the company board of directors is "100 percent" behind the strategy.

Kalla, who kept her "outperform" rating on the stock, said she remains optimistic that Ciena can pull out of its recent troubles. The company's current market value is equal to its cash on hand, a classic sign that a stock has bottomed out. She also said the company was an acquisition candidate.

"Ciena still has a $300-to-$400 million business," she said. "The problem right now is that its old business is ramping down significantly, and its new business isn't ramping up yet."

Ciena Corp. stock closed yesterday at $2.08 a share, its lowest price ever, after the company said it would report lower revenue than expected in its third fiscal quarter.